Underwater electrical cables and marine conductors in general cause major problems when they begin to leak. Leakage of course is common due to the fact that such cables, and their connectors, commonly operate in subsurface environments or in near surface atmospheric environments characterized by extreme salt and humidity. The primary water and humidity sealing means in underwater connectors is generally the insulation encapsulating the strands of individual conductors, or it is an encapsulating plastic around the machined stainless steel connector. Frequently, these connectors are made of corrosion resistant metals, such as stainless, or the like, and are coated with a plastic coating for the purpose of precluding entry of moisture.
Further, in marine seismic operations, underwater electrical plugs or connectors are needed to connect power and instrumentation conductors to other equipment, such as seismic sound generators, i.e., air guns. These "guns" are used as a sound source to obtain acoustic reflections from the sea-floor. Typically, they are fired every ten to fifteen seconds producing extremely strong pressure waves. As a result, the electrical cables, conductors and connectors are subjected to a great deal of structural abuse, and normally they may not last for extended periods of time before developing leaks or other operational defects. Therefore, all of the electrical connectors and other components used in these harshest of environments must necessarily withstand repeated explosive forces on their exteriors while allowing for a degree of flexibility there within lest the internal conductor be jolted loose from its external housing. In addition, these electrical connectors must be able to withstand corrosive environments such as in sub-sea, swamp and marsh operations.
The inventor originally believed that the best way to obtain a marine electrical connector which would satisfactorily handle the type of punishment which would be incurred, based upon the foregoing conditions, was by having a rigid or very strong external housing material which would not fracture while simultaneously precluding leakage from the environment and mounting the electrical conductor inside the housing within a flexible shock absorbent material. The shock absorbent material was to allow for the repeated percussive forces, which would be incurred without producing a short in the circuit. This previous invention is described and claimed in U.S. Pat. No. 5,120,268, which was issued on Jun. 9, 1992. In that application, the Applicant pointed out that he was unaware of electrical conductors which utilized flexible shock absorbent interiors, and that it was common for the exterior and interior of electrical connectors to be comprised of different materials, such as, for example, metal and rubber, thus requiring difficult and expensive bonding techniques which frequently result in unreliable adhesion. Applicant further notes, that this is believed to be true whenever different materials of substantially different hardness and/or density are bonded together. Applicant's concepts remain true to date and the present invention expands upon those principals in light of the development of a new and improved marine electrical connector.
Applicant's main advantage with respect to the previous invention was that two types of plastic were utilized to comprise the electrical connector and the connectors were not made of stainless steel or any other metal alloy normally resistant to corrosion and other abusive environmental conditions, thereby greatly decreasing the cost of the connector. Instead, Applicant utilized a method for making reliable, multi-component, electrical connectors which, theretofore, were not capable of a reliable, permanent fusion to one another. The dual material electrical connector of the invention was characterized by a flexible shock absorbent internal core and relatively hard external housing each fusionly connected to one another in an irrevocable bond. Applicant discovered the use of the glass impregnated external housing consisting of a hard plastic material and an interior shock absorbent material of substantially the same plastic which obviated the short comings of the prior art. This combination not only enabled the production of electrical connectors having operational advantages over that which had been known theretofore, but it also markedly simplified the manufacturing of connectors and reduced the expense thereof.
In the present invention, Applicant has designed away from the hard external housing and instead now utilizes a soft plastic external housing which is fused to a connector element and which is still more than sufficiently capable of withstanding the shocks and abuses incurred by marine electrical connectors and is even less susceptible to leakage than the prior art. Further, the present invention greatly reduces the steps required to manufacture the connector, thereby, once again, reducing cost and time in the manufacturing process, while yielding an even more desirable end product. The present invention is also even more capable of providing leakage protection and withstanding harsh and corrosive environmental elements and operational conditions than the prior art connectors.